1. Field of the Invention
This invention relates generally to computer data storage drives and more specifically to a negative air pressure air bearing slider structure employed in conjunction with data storage drives.
2. Description of the Related Art
The negative pressure air bearing slider designs of the prior art are generally preferable to conventional flat taper slider configurations. The negative pressure structure enables the utilization of low suspension preloads, yielding decreased stationary frictional forces. These forces are oftentimes referred to as xe2x80x9cstictionalxe2x80x9d forces. Negative pressure structures also offer the potential for improved stop/start performance.
One shortcoming of state-of-the-art negative pressure air bearing designs is that the slider produces large negative loads. An example of such a design is disclosed in the Warner et al. reference, U.S. Pat. No. 4,475,135. These structures achieve a high air bearing stiffness which improves the compliance to the disk, but also increases the impact forces resulting from asperity and third-body contact. Such high-impact forces tend to degrade device reliability. Consequently, a structure offering the ability to optimize the amount of stiffness or negative pressure would be desirable. Another drawback of the prior art negative pressure air bearing is its high skew sensitivity. For zone bit recording applications, it is advantageous to maintain a constant spacing profile, but in rotary actuator file environments, the skew angle varies across the data band. Highly skew sensitive negative pressure designs experience high roll under these conditions resulting in a non-flat spacing profile. Thus, a negative pressure air bearing which is insensitive to skew would be desirable.
Although it is possible to adjust the amount of stiffness on existing slider structures by increasing the depth of the etched relief, this approach has significant drawbacks. Deepening the etched relief increases the fly height sensitivity of the slider structure. Furthermore, the reverse air current flow within the depths of the etched relief will be increased, thereby increasing the slider""s propensity to accumulate debris. Therefore, it would to be desirable to develop a technique for adjusting the negative pressure of the slider structure which is independent of the etch depth. It would also be desirable to provide a means for flushing debris through and out of the air bearing. It would also be desirable to provide an air bearing structure having improved static and dynamic performance over existing structures.
The air bearing slider of the present invention provides a structure which optimizes the amount of negative pressure provided by the slider structure. This slider is employed in conjunction with a data storage medium which may be engaged in motion relative to the slider. The slider structure includes a leading edge and a trailing edge, the edges being determined with reference to the motion of the data storage medium. The slider also includes a bottom surface which faces the data storage medium. The bottom surface extends between the leading edge and the trailing edge.
The negative pressure contours of the slider are determined by means of a U-shaped rail situated between two outer taper-flat pads on the bottom surface. The amount of negative pressure is controlled by adjusting the length and width of the area enclosed by the U-shaped rail. The two outer taper-flat pads provide roll stiffness. These pads may be extended to the trailing edge of the slider to provide a mounting location for a read/write element. Skew insensitivity is achieved by adjusting the relative widths of the U-shaped rail and the outer taper flat pads. The channels formed between the U-shaped rail and the outer taper flat pads provide a constant flow through the slider which flushes contamination. In this manner, the negative pressure contours may be optimized for specific device applications.
A second embodiment of the invention includes an isolated island positioned between the legs of a U-shaped rail. The purpose of the island is to provide means for mounting a read/write element to the slider. Two outer pads are employed for improving the roll stiffness characteristics of the slider. These pads may be offset from the trailing edge toward the leading edge of the slider to minimize roll sensitivity.
A third embodiment of the invention includes element mounting means in the form of a center rail extending from the U-shaped rail to the trailing edge of the slider structure. Two outer pads are employed, which may be offset from the trailing edge toward the leading edge of the slider to minimize roll sensitivity.
According to a fourth embodiment of the invention, the U-shaped rail can be situated at a position on the bottom surface between the leading and trailing edges of the slider structure. Centering the U-shaped rail between the lateral edges of the slider provides enhanced pitch angle and fly height design flexibility.
In an alternative embodiment of the slider, two U-shaped rails are spaced laterally on the bottom surface near the slider leading edge. Independent adjustment of the area enclosed by each U-shaped rail, as well as the relative widths of the inner and outer rails, provides enhanced skew insensitivity over previous embodiments.